Are the Devs aware of the unlocked core for PS4? And will they use it?

[Lemuria]

The PS4 may not utilize DirectX, but the primary engine developed by SE does for portability reasons. Otherwise you'd see much wider gaps between PS4 and PC effects and performance.

A quick Google search will tell you that this is not true. The PS3/PS4 versions of FFXIV use OpenGL, which is entirely different to DirectX. The reason you don't see as big of a performance gap is because the engine is built with that in mind and designed specifically for the hardware, just like all good console games.

Stuff like that is why a relatively low spec console (low spec compared to gaming PC's at least) can still output amazing graphics on par with the best computers. Fixed hardware is easier to make games for, because you know exactly what's in it. PC's can be all kinds of Frankenstein's monsters, with different CPU's different memory, different graphics cards and so on.